Search Operation
When another hurricane struck the base, it became clear that life on Mars was not just an interesting adventure, but a dangerous struggle for survival. Thick red dust shrouded the horizon, and powerful gusts of wind howled like a giant beast prowling the desert. It was in this storm that they lost one of the supply modules – it had been swept far away from the base.
Althorn tried to remain calm, but even he understood they wouldn’t last long without food. When the wind died down slightly, he gathered the children and said:
“We need to find that module, but heading out into the storm without landmarks is suicide. A stroboscope will help us,” he said with a confident smile.
“What is a stroboscope?” Zorin asked, knitting his brows.
“It’s a device that flashes with bright bursts of light. On Earth, it’s used everywhere: on airplanes to mark their position, on lighthouses so ships don’t lose their way. Even bicycles have stroboscopes installed so they can be seen in the dark,” Althorn explained. “Stroboscopes save energy because they don’t shine constantly; they flash. In a dust storm, this could be the deciding factor.”
“But how will that help us?” Melia asked, watching her father with curiosity.
“We can use the stroboscope as a beacon to find our way back, even if everything around us is swallowed by dust,” Althorn said. “To do this, we’ll use LEDs, just like they do on Earth.”
He opened his toolbox and began laying out parts. It looked like an ordinary lesson, but everyone understood that their lives were on the line. Althorn took out a small LED and showed it to the children:
“In modern flashlights, incandescent bulbs haven’t been used for a long time; they’ve been replaced by small, durable, powerful, and energy-efficient LEDs. Because of them, flashlights can last much longer. These LEDs connect to a smart control board that can not only turn the light on and off but also manage different operating modes—for example, adjusting brightness or turning on the strobe.”
“Are those the modes found on bicycle lights?” Zorin asked.
“Yes, exactly,” Althorn replied. “Bicycle lights often use stroboscopes so that cyclists are visible at night. At the same time, this mode helps save battery life, since a flashing light is turned off half the time it’s working. Today, we’re going to build and program such a universal flashlight.”
While Althorn explained the mechanics of a stroboscope, they assembled the circuit elements together. Melia connected the LED to the board, while Zorin handled the resistors and the potentiometer.
“Now it’s important to understand how to control the brightness,” Althorn continued. “We’ll use a method called Pulse Width Modulation (PWM).”
“What is that?” Melia asked.
“Pulse Width Modulation (PWM) is a way of controlling power where the LED is turned on and off very rapidly,” Althorn explained. “The longer the LED stays on during a single cycle, the brighter it will appear to shine. For example, if the light is on half the time, the LED will look dimmer, but we’ll save energy. This is especially important given the limited power supply on Mars.”
Zorin thought for a moment and asked, “How does that work in practice?”
Althorn smiled and explained: “Imagine we have a switch that can turn the LED on and off very quickly. This process is PWM. We can adjust how much time during one cycle the LED is turned on. If the light is on 75% of the time, it will shine brighter; if it’s only on 25%, it will be dimmer. This method allows us to not only change brightness but also conserve energy.”
He continued: “This is a very common method of light control on Earth. It’s used, for example, to control the brightness of displays and backlighting in mobile devices and monitors. Low-frequency amplifiers also use this method to minimize energy loss and maintain high efficiency.”
The children listened intently, absorbing the technical details.
“For us, this means we can control the brightness of our stroboscope so that it shines brighter during a heavy storm and dimmer when we need to save energy,” Althorn summarized.
“Well, let’s begin,” Althorn said, and they started assembling the device.
“I’m very hungry,” Melia complained, rubbing her stomach.
“Be patient, dear. Engineering doesn’t tolerate rushing,” Althorn replied with a kind smile and handed her a small ration set aside for emergencies. “Here, have a snack for now. Soon we’ll have our supplies back.”
When the stroboscope was finished, Althorn and Zorin looked at their work with pride. The device was ready to light their path through the Martian storms. Althorn turned it on, and the LEDs began to flash with bright, sharp bursts.
“Well, shall we head out now?” Zorin asked, his voice filled with excitement.
“Yes, son, it’s time to act,” Althorn nodded.
They put on their spacesuits, took the stroboscope, and headed for the rover. While Lirania and Melia remained at the base, Althorn and Zorin set off to find the food module, hoping their new stroboscope would lead them out of this deadly trap.